filtering long prefixes

Daniel Karrenberg Daniel.Karrenberg at
Sun Oct 8 11:26:05 UTC 1995

  > Willi Huber <huber at> writes:
  > the Municipality of Zuerich has got assigned 1/2 class B in April this year
  > after a long discussion with RIPE NCC. They will soon get onto Internet.
  > I need to be sure that this address space is routed on the Internet.
  > Sean, Geert-Jan, could you comment, please.


as far as the RIPE NCC is concerned we see this as follows:

1) All major transit providers are capable and willing to route fully
classless, so we can assign address space in a classless manner. 

2) Some service providers apply route filtering based on prefix length
or other general criteria.  This is a matter of the service providers
concerned and we have no control over it.  The proper way to resolve
problems caused by this is to talk to the service provider concerned. 
Of course we will be happy to help if we can. 

3) We inform service providers about the RIPE NCC assignment policies in
the appropriate fora such as RIPE WGs, NANOG and IETF CIDRD WG.  This
enables service providers to take assignment policies into account when
defining their routing policies. 

4) We examine routing policies of service providers which are brought 
to our attention and provide feedback to the providers if we detect
potential problems due to our assignment policies.

5) Service providers are invited to contribute to the definition of 
RIPE NCC assignemnt policies via the RIPE Local IR WG.

In the particular case at hand we have informed Sprint (and everyone else)
about the fact that we assign prefixes longer than /16 in the B space 
and Sprint have informed us that they currently see no problem routing
these unless they can be aggregated to /16s or shorter.
So your customer should not have a problem with Sprint.

If you have any further questions, please do not hesitate to contact us.


Daniel Karrenberg
RIPE NCC Manager

PS: Sorry about the delay caused by illness.

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